Argon grades and purity
Argon (Ar) is a genuinely inert noble gas — it will not react with molten metal at any welding temperature, which is why it is the backbone of TIG and MIG shielding. It is also denser than air, so it blankets a weld pool and stays there rather than drifting off.
Purity matters more in argon than most buyers expect. Oxygen and moisture contamination shows up directly as porosity and discolouration in the weld, particularly on stainless steel, aluminium and titanium.
| Grade | Typical purity | Where it is used |
|---|---|---|
| Welding-grade argon | 99.95% – 99.99% | TIG (GTAW) and MIG (GMAW) on steel, stainless and aluminium |
| High-purity argon | 99.999% | Titanium and reactive-metal welding, heat treatment, sintering |
| Ultra-high-purity argon | 99.9995%+ | Analytical instruments, ICP, gas chromatography, semiconductor work |
| Argon-CO₂ mixtures | Blended to spec (e.g. 80:20, 82:18) | MIG welding carbon and low-alloy steel — better arc stability and less spatter |
| Argon-helium mixtures | Blended to spec | Thick-section aluminium and copper, where more heat input is needed |
Argon specification in India is commonly cited against IS 5760. Confirm the exact revision required by your customer or inspection authority before order, and we will supply and certify against it.
What argon is used for
- ✓TIG (GTAW) welding — the standard shielding gas for stainless steel, aluminium, copper and titanium
- ✓MIG (GMAW) welding, usually as an argon-CO₂ mixture on carbon and low-alloy steel
- ✓Plasma cutting and plasma welding
- ✓Root purging and back-purging of stainless steel pipe welds to prevent sugaring
- ✓Bright annealing, sintering and controlled-atmosphere heat treatment
- ✓Blanketing molten metal and degassing in aluminium and steel casting
- ✓Carrier and plasma gas for analytical instruments — ICP-OES, ICP-MS and GC
- ✓Filling gas for double glazing and specialist lighting
Choosing the right shielding gas
| Job | Gas | Why |
|---|---|---|
| TIG, stainless steel | Pure argon 99.99% | Full inertness; any oxygen shows as discolouration and loss of corrosion resistance |
| TIG, aluminium | Pure argon, or argon-helium for thick section | Argon gives good cleaning action; helium adds heat for heavy plate |
| MIG, carbon steel | Argon-CO₂ 80:20 or 82:18 | CO₂ adds penetration; argon keeps the arc stable and cuts spatter |
| MIG, stainless steel | Argon with low CO₂ or O₂ addition | Minimises carbon pick-up while keeping the arc stable |
| Titanium and reactive metals | High-purity argon 99.999%, with trailing shield | These metals will absorb any oxygen or nitrogen present and embrittle |
| Stainless pipe root runs | Argon back-purge | Prevents oxidation ("sugaring") on the inside of the joint |
Tell us the parent metal, thickness and process and we will recommend the gas — including when a cheaper mixture will do the same job as pure argon.
How argon is supplied
| Packaging | Typical content | Suits |
|---|---|---|
| 47 L high-pressure cylinder | ~7 m³ at 150 kg/cm² | Fabrication shops, site welding, maintenance work |
| Cylinder bank / quad | Multiples of cylinder content | Production welding lines and continuous fabrication |
| Manifolded bank with changeover | Continuous | Shops that cannot stop mid-weld to change a cylinder |
| Pre-blended mixture cylinders | To specification | Argon-CO₂ and argon-helium shielding mixtures, blended and certified |
Cylinder identification and handling
Under IS 4379, argon cylinders are peacock blue with no neck band, marked with the gas name and formula.
Argon is non-flammable and non-toxic, but it is denser than air and a simple asphyxiant — it pools in pits, trenches, tank bottoms and any low-lying space, and it does so without smell or visible sign. Welders working in confined spaces are the group most at risk, precisely because good shielding means a steady argon flow into an enclosed volume.
- ✓Ventilate confined and low-lying work areas; monitor oxygen where argon flows continuously
- ✓Store and transport upright and secured, with valve caps fitted
- ✓Use the correct regulator and flowmeter for argon — do not adapt fittings from another gas
- ✓Set flow to the recommended rate for the torch and joint; excess flow wastes gas and can draw in air by turbulence
- ✓Keep cylinders clear of the welding arc, earth returns and heat
Why buy argon from IIGAS
IIGAS has supplied industrial gases since 1947 and sits on the BIS committees CHD 6 (Industrial Gases) and MED 16 (Gas Cylinders). Argon is supplied with documented purity, correct cylinder identification and mixtures blended and certified to your specification rather than to a nominal label.
Because we also build gas plants and cylinder-filling stations, we understand what your welding shop actually needs from a supply — consistent purity, reliable changeover and cylinders that arrive when the job needs them.
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